216 CILIATE FIBRILLAR SYSTEMS 



ascribed in the literature to each of these fibrillar mechanisms, as illustra- 

 tive for similar systems that have been studied thus far in a large number 

 and variety of other ciliates. 



It will be recalled that Ehrenberg (1838) saw in the "stalk muscle" 

 of Vortkella cross striations which he regarded as comparable to those 

 of the striated muscles of other animals. Also, he detected both longi- 

 tudinal and circular fibers in the body of several other vorticellids. Quite 

 in line with his search for such comparisons, he attributed to all of these 

 fibrils a contractile function. For him they were literally miniature 

 muscles which had their structural and functional counterparts in the 

 muscles of macroscopic organisms (Maupas, 1883). Evidently, Ehren- 

 berg's comparison between microorganisms and macroorganisms led him 

 to look for a one-to-one correspondence between microorgans and 

 macroorgans. 



It will be recalled that what Ehrenberg regarded as the stalk muscle 

 (Stielmuskel) was analyzed into several components by later investi- 

 gators. These, according to Entz (1893), included: a cross-striated, rod 

 or band-like Spasmonem, and another rod-like strand, the Axonem, 

 around which was coiled the Sphonem. Each of these was, in turn, 

 analyzable into longitudinal fibrils, whose properties apparently ac- 

 counted for their birefringence and cross striations. The Spasmonem and 

 Spironem showed also, spiraling within their own spiral strand just 

 outside its longitudinal fibrils, a fine fibrillar coil coursing throughout 

 their length. Also, both Spironetn and Axonem had, centrally located, 

 the "cytophanes" which, with their longitudinal interconnections, ap- 

 peared like a string of pearls. Thus Ehrenberg's "Stielmuskel" turns out 

 to be a highly complex mechanism which is structurally quite different 

 from the "muscles of other animals" to which he had compared it. 



Finally, mention was made also of the circular and longitudinal 

 myonemes of the protoplasmic lining of the style sheath, which are 

 continuations of the outer fibrillar complex of the body myonemes. 



Taking into account this assemblage of highly differentiated com- 

 ponents within the stalk of the Contractilia, together with a few rather 

 inconclusive experimental results, various interpretations were advanced 

 to account for both the contraction and the extension of this stalk. These 

 may be summarized as follows: 



1. The majority of investigators agree that the quick spiraling con- 



